In connection with the operation of large semi-trailer trucks, the tractor unit is used to transport the trailer unit to a distant point. When the trailer unit has been delivered, the tractor unit does not become a useful work vehicle, unless there is another trailer available which is to be transported. With the development of the portable flatbed unit of the present invention, after a trailer has been delivered, it is possible to convert the tractor unit into a flatbed truck. Thus, when the semi-trailer truck has reached its destination and the trailer has been disembarked, it is possible to convert the vehicle to a flatbed truck either for local hauling or long distance hauling. In this manner, the likelihood of a tractor unit having to be transported a long distance without a load is substantially diminished.
The present invention represents an improvement over the portable flatbed truck of the copending application, in that the pulley system has been given added capabilities, and a motorized winch has also been incorporated. Accordingly, through the operation of the new pulley system, it is not only possible to move the flatbed sections but additionally, the fifth wheel can be moved into and out of engagement with the flatbed sections.